国家地理 春秋分（在线收听）

Twice a year, day and night, fall into balance, lasting for nearly equal length. Known as equinoxes, Latin for equal night, they occur in March and September and along with solstices mark the changing of seasons as Earth travels around the sun.

一年有两次，昼夜平衡，时长几乎相等。在拉丁语中，equinoxes（二分日）是“昼夜相等”的意思，出现在3月和9月，它们和二至日一起标志着地球围绕太阳运转造成的季节变化。

Astronomers like to describe the equinox within the conceptual celestial sphere. Here the heavens are projected around the Earth, like an enormous planetarium. The model is bisected by the celestial equator, a projection of Earth's own equator. The equinox occurs at the point at which the sun's path or ecliptic crosses the celestial equator. In spring it is known as the vernal equinox, and in fall the autumnal equinox.

天文学家喜欢在假想的天球中描述春秋分。在天球中，天空被投射到地球周围，就像一个巨大的天文馆。这个模型被天球赤道平分，天球赤道是地球自身赤道的投影。二分日通常出现在太阳的路径或黄道与天球赤道相交时。春天是春分，秋天是秋分。

The other two seasonal points on the sun's path are the two solstices; in the northern hemisphere, the summer solstice marks the longest day of the year, while the winter solstice marks the shortest. The seasonal aligning of the sun has been more than just a unique celestial event for humankind throughout history. Ancient sites like Stonehenge in England and Machu Picchu in Peru have well documented solar alignments during the solstices.

太阳路径上的另外两个季节点是两个至日；在北半球，夏至是一年中白昼最长的一天，而冬至则是最短的一天。对历史上的人类来说，太阳的季节性移动不仅仅是一个独特的天体事件。像英格兰的史前巨石阵和秘鲁的马丘比丘这样的古代遗址详细记录了二至日时太阳的移动。

Similarly, the equinoxes have been associated with some amazing man-made phenomena. In the ancient Maya city of Chichén Itz the great pyramid known as El Castillo is oriented along cardinal axis. During the equinoxes, shadows cast by the railings create the illusion of a writhing serpent body, descending the northern steps where it joins the carved serpent's head at the base of the stairway. The cultural significance of the fall equinox and changing of seasons continues today, especially in the northern hemisphere, where the autumnal equinox occurs around harvest season.

同样，二分点也与一些令人惊异的人造现象有关。在古玛雅城市奇琴伊察，被称为埃尔卡斯蒂略的大金字塔沿主轴建造。在二分日，栏杆投下的阴影仿佛蛇扭曲的身体，从北边的台阶往下延伸，在阶梯的底部与雕刻的蛇头会合。秋分和季节变化的文化意义一直延续到今天，尤其是在北半球，秋分发生在收获季节。

In fact, the full moon nearest the autumnal equinox is commonly referred to as the harvest moon. In China and other Asian countries, this time is celebrated with the mid-autumnal festival; the origins are linked to the birth of the moon goddess and festival traditions revolve around families with reunions and feasts and special moon cakes. In Jewish culture, thanks for the harvest is given during the week long Feast of the Tabernacles or Sukkot. Families eat meals in temporary shelters outside, recalling the Israelites' days in the wilderness after the Exodus from Egypt.

事实上，最接近秋分的满月通常被称为收获的月亮。在中国和其他亚洲国家，人们在这个时候会庆祝中秋节；中秋节的起源与月亮女神的诞生有关，中秋节的传统主题是家庭团聚、盛宴和特殊的月饼。在犹太文化中，人们会庆祝为期一周的住棚节(Sukkot)以感激丰收。一家人在外面的临时住所里吃饭，回忆以色列人出埃及后在旷野里的生活。